theorem ModalWorld.mk.sizeOf_spec
theorem ModalWorld.mk.sizeOf_spec
: ∀ (holds : Prop → Prop) (intro : ∀ (p : Prop), p → holds p) (mp : ∀ (p q : Prop), holds (p → q) → holds p → holds q)
  (consistency : ¬holds False) (elim : ∀ (p : Prop), holds (holds p) = holds p),
  sizeOf (r0nkgtza.ModalWorld.mk holds intro mp consistency elim) = 1